This application claims the priority of German patent document 100 47 746.1, filed Sep. 17, 2000, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a method for longitudinal control of a vehicle having a vehicle navigation system.
Such a control system is disclosed for example, in German Patent Document DE 196 38 511 A1. In particular, cruise control systems of this type control the driving and/or braking systems of a vehicle such that either a desired speed or a desired distance from the preceding vehicle is set. In a method disclosed in German Patent Document DE 196 38 511 A1, such cruise control systems are supplied with information of a navigation system that is also present in the vehicle. For this purpose, for example, a control unit assigned to a longitudinal control system may have an interface to the electronic system of the navigation system.
Known longitudinal control systems have been designed to accelerate automatically to a desired speed when a follow-on drive (with a defined desired distance) is terminated, for example when the vehicle changes to a free lane or a preceding vehicle changes lane. However, even when using information of a navigation system, no reliable detection of the lane change has thus far been possible because, due to tolerances in the road nets stored in the navigation, and in the sensors used to determine the position of the vehicle (GPS).
The presence or absence of a preceding vehicle (target object) in the vehicle""s own lane also cannot be with a sufficiently high reliability by means of ranging sensors (radar, ultrasound, infrared as well as image processing) because the detection range (detection angle) of the sensors is relatively small.
One object of the invention is to assess certain lane changing situations using information of the navigation system.
Another object of the invention is to distinguish a lane changing situation from a cornering, in which a loss of the target object occurs without a lane change.
These and other objects and advantages are achieved by the method and apparatus according to the invention in which, during a longitudinal control operation based on a defined desired distance from a preceding vehicle, information from the navigation system is used to determine the probability that the preceding vehicle and/or the own vehicle is cornering when the preceding vehicle is no longer detected. A longitudinal acceleration is carried out with a time-delay when the probability is higher than a defined (variable or fixed) threshold.
To determine the probability that the preceding vehicle and/or the own vehicle is cornering, the road type (turnpike, country road; number and/or width of the lanes of a road; degree of curvature of the course of the road; turn-off possibilities) is analyzed. Information concerning the road type is available by way of the navigation system.
To determine the probability that the own vehicle is cornering, additional values relating to driving dynamics (steering angle, yaw rate, lateral acceleration) may be analyzed. Such information is determined by means sensors inside the vehicle.
The process according to the invention is preferably integrated in a control unit which is otherwise already provided for a longitudinal control system. For this purpose, only an interface to the navigation system must be established.
The extraction and processing of information from the navigation system to determine the actual and future context according to the invention permits an adaptive control of the longitudinal dynamics based on the respective situation, and is typical with respect to the driver by means of a longitudinal control system. The operating quality and the driving comfort are increased.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.